Sharing an node app is really easy and fast.
Let's take an example you have a project like
>Project1
| -> node_modules
| -> src
|-> app.js
| ->package-lock.json
| ->package.json
To share your project, you just have to share package.json and code files.
>Project1
| -> src
|-> app.js
| ->package.json
When someone wanted to use this project, they can simply run.
> npm i
inside the project directory, npm will install all dependencies mentioned in the package.json and make the application functional.
We upload to NPM the same way with just different commands
detailed explanation about sharing your code